1. Field of the Invention
This invention relates to instrumentation and a technique for measuring local cerebral blood flow and intracranial pressure, and more particularly, to a ventriculostomy tube having the capability of simultaneously and continuously measuring on a real time basis both intracranial pressure and local cerebral blood flow.
2. Description of the Prior Art
Ventriculostomy tubes have been used for many years to measure intracranial pressure to assist in diagnosing and treating various pathologic conditions of the brain. This instrument is inserted into a ventricle in the brain through a drilled aperture in the skull to directly and continuously measure the absolute value of intracranial pressure at a given site.
Different types of instrumentation have been developed to measure local cerebral blood flow in the brain. Generally, such instrumentation typically utilizes multiple sensors which are inserted into the brain at two different sites through two separate drilled apertures or rely on a single brain probe and a separate probe inserted into a blood vessel at a site remote from the brain. None of these prior art devices provides for simultaneous measurement of both intracranial pressure and local cerebral blood flow (LCBF) or utilizes an instrument capable of being inserted through a single aperture in the skull even though it is generally recognized that the probability of brain injury is substantially enhanced by the insertion of multiple probes at multiple brain sites. In addition, some prior art devices provide a delayed response to changes in local cerebral blood flow or provide relative rather than absolute LCBF readouts.